1. Field of the Invention
The present invention relates to the fields of reproductive biology and reproductive endocrinology. More specifically, the present invention discloses a hormone normalization therapy and its use in the prevention of infertility, miscarriages, stillbirths, and birth defects.
2. Description of the Related Art
Incidences of infertility, trisomic birth defects, and miscarriage undergo marked increases in women as they age (FIGS. 1A-1B). Women over the age of 35 are particularly vulnerable to these adverse reproductive outcomes. Nonetheless, the birth rates among women of advanced maternal age have increased significantly over the past 25 years because the average age for women to attempt to have a baby has increased dramatically (FIG. 2). Women aged 35 and older (“advanced maternal age” or “AMA”) gave birth to 586,000 babies in the U.S. in 2004. This trend is particularly evident in westernized societies where education and career opportunities often delay marriage and childbearing. In Canada, for example, there has been an 83% increase in the number of babies born to advanced maternal age women just in the period of 1991 to 2000.
The delay in childbearing seen in the U.S., Canada, Europe, and Japan puts an increasingly greater number of women at risk of infertility, miscarriages and birth defects The combination of increased risk of infertility and pressure to have children later in life means that that these women are trying much harder to have babies than they did in the past. Based on conservative estimates obtained from statistics at the U.S. Government Census Bureau, there are 2,620,500 infertile American women aged 35-39, and 6,376,000 infertile women aged 40-44 (United States National Population Estimates, 2000-2005). An increasing percentage of women in this age group want to have a baby, but they cannot get pregnant. In addition, 127,000 US pregnancies per year for women over 35 are miscarried, out of 713,000 pregnancies. Although modern medicine has extended life expectancy, there have been no therapeutic advances to prevent chromosomal abnormalities from occurring when a woman uses her own eggs. Amniocentesis and other chromosomal abnormality tests lead to elective abortion of thousands of fetuses with trisomic birth defects. Some parents choose to continue their pregnancy and give birth to children with serious trisomic birth defects.
A primary cause of infertility, miscarriages and birth trisomic pregnancies is aneuploidy in the conceptus due to errors of chromosome segregation in the oocyte during meiosis. These errors create a fertilized embryo that has an extra copy of a given chromosome (trisomy), or just one copy of that chromosome (monosomy). The increase in miscarriage rates in AMA women is primarily attributable to trisomic conceptions. Whereas only 8% of embryos from women in their early to mid 20s are chromosomally abnormal, 84% of embryos from women 35-39 are chromosomally abnormal, as are nearly all embryos from women over 40.
Greater than 90% of miscarriages and a large percentage of the increased incidence of infertility with age are caused by chromosomal and genetic errors in the embryo. Monosomic conceptions manifest as infertility. Trisomic conceptions manifest as infertility, miscarriages, stillborns, or birth defects, depending on the identity of the malsegregated chromosome. Trisomies 21, 18, and 13 cause Down, Edward and Patau syndromes, respectively.
Advanced maternal age women often display significantly elevated follicle stimulating hormone (FSH) and/or 17-bEstradiol (E2) levels during their menstrual cycles, compared to younger women. The menstrual cycles of advanced maternal age women, particularly the follicular phases, are significantly shorter than those of young women. The luteinizing hormone (LH) surge occurs much earlier in advanced maternal age women than in younger women.
Gonadotropin and steroid hormones are potent regulators of the developmental events occurring in follicular cells and oocytes that terminate in meiosis and ovulation. A number of studies have shown that FSH, E2 and LH work in concert to orchestrate follicular development and many processes in the oocyte, including meiotic maturation and progression, nuclear and cytoplasmic maturation, centrosomal and cytoskeletal organization, and the resumption of meiosis. Changes in the intrafollicular microenvironment caused by perturbations in levels of FSH and E2, and changes in the timing of follicular and oocyte maturation relative to changes in gonadotropin and steroid hormone levels across the cycle caused by a short follicular phase, can significantly compromise the developmental integrity and timed meiotic progression of the follicle and the oocyte.
High FSH and E2 are associated with increased incidences of infertility, miscarriages, and aneuploid conceptuses in animals and in women. A short menstrual cycle length and follicular phase in women are also associated with infertility and miscarriages in women. High levels of exogenously administered FSH, E2, and other estrogenic compounds have been shown in a number of studies to cause spindle disruption, chromosome disorganization, aneuploid conceptions, and pregnancy losses. Since gonadotropin and steroid hormones control the fine-tuned processes that orchestrate meiotic maturation and progression, and since exogenously administered FSH and E2 cause aneuploidy, elevated endogenous FSH and E2 likely contribute to aneuploidy in advanced maternal age women.
Trisomy of chromosome 21 causes Down syndrome, a severe condition characterized by mental retardation, susceptibility to infection, cardiac defects, a high incidence of Alzheimer's dementia, and a short lifespan. Several other chromosomes also experience chromosome segregation problems with increased frequency in advanced maternal age. Trisomies of chromosome 18 and chromosome 13 cause Edward and Patau syndromes, respectively, two extremely severe birth defects that cause mental retardation and cardiac defects, and are fatal within several weeks or months of birth. Most Down syndrome babies (80% of all conceived babies with Down syndrome) as well as babies with Patau and Edward's syndromes are not born alive because they fail to make it to term or they are stillborn. Trisomies of a variety of other chromosomes (predominantly 14, 15, 16, 22) cause miscarriages in many patients, and a number of other trisomies as well as monosomic conceptions are lethal in the peri-implantation period and manifest as infertility. Trisomic birth defects, stillbirths, miscarriages, and infertility caused by aneuploidy create profound suffering for parents, their offspring, and the immeasurable loss of those children who were not born.
Thus, the prior art is deficient in therapies designed to prevent infertility, miscarriage and trisomic birth defects caused by aneuploidy. The present invention fulfills this long-standing need and desire in the art.